Abstract.A model of iodine chemistry in the marine boundary layer (MBL) has been used to investigate the impact of daytime coastal emissions of molecular iodine (I 2 ). The model contains a full treatment of gas-phase iodine chemistry, combined with a description of the nucleation and growth, by condensation and coagulation, of iodine oxide nano-particles. In-situ measurements of coastal emissions of I 2 made by the broadband cavity ring-down spectroscopy (BBCRDS) and inductively coupled plasmamass spectrometry (ICP/MS) techniques are presented and compared to long path differential optical absorption spectroscopy (DOAS) observations of I 2 at Mace Head, Ireland. Simultaneous measurements of enhanced I 2 emissions and particle bursts show that I 2 is almost certainly the main precursor of new particles at this coastal location. The ratio of IO to I 2 predicted by the model indicates that the iodine species observed by the DOAS are concentrated over a short distance (about 8% of the 4.2 km light path) consistent with the intertidal zone, bringing them into good agreement with the I 2 measurements made by the two in-situ techniques. The model is then used to investigate the effect of iodine emission on ozone depletion, and the production of new particles and their evolution to form stable cloud condensation nuclei (CCN).
Acute kidney injury (AKI) frequently afflicts patients undergoing cardiopulmonary bypass (CPB) and independently predicts death. Both hemoglobinemia and myoglobinemia are independent predictors of postoperative AKI. Release of free hemeproteins into the circulation is known to cause oxidative injury to the kidneys. This study tested the hypothesis that postoperative AKI is associated with both enhanced intraoperative hemeprotein release and increased lipid peroxidation assessed by measuring F 2 -isoprostanes and isofurans. In a case-control study, nested within an ongoing randomized trial of perioperative statin treatment and AKI, we compared levels of F 2 -isoprostanes and isofurans with plasma levels of free hemoglobin and myoglobin in 10 cardiac surgery AKI patients to 10 risk-matched controls. Peak plasma free hemoglobin concentrations were significantly higher in AKI subjects (289.0±37.8 versus 104.4±36.5 mg/dl, P=0.01), whereas plasma myoglobin concentrations were similar between groups. The change in plasma F 2 -isoprostane and isofuran levels (repeated measures ANOVA P=0.02 and P=0.001, respectively) as well as the change in urine isofuran levels (P=0.04) was significantly greater in AKI subjects. In addition, change in peak plasma isofurans levels correlated not only with peak free plasma hemoglobin concentrations (r 2 =0.39, P=0.001) but also with peak change in serum creatinine (r 2 =0.20, P=0.01). Postoperative AKI is associated with both enhanced intraoperative hemeprotein release and enhanced lipid peroxidation. The correlations among hemoglobinemia, lipid peroxidation, and AKI indicate a potential role of hemeprotein-induced oxidative damage in the pathogenesis of postoperative AKI. KeywordsAcute kidney injury; oxidative stress; isoprostanes; isofurans; hemeprotein; cardiac surgery; cardiopulmonary bypass; NGAL Acute kidney injury (AKI) complicates the postoperative course in up to 30% of all cardiac surgery patients and independently predicts in-hospital mortality, morbidity, and mid-term and long-term survival. [1][2][3] Renal hypoperfusion, use of cardiopulmonary bypass (CPB), © 2010 Elsevier Inc. All rights reserved.Correspondence: Mias Pretorius, MBChB, MSCI, 561 PRB, Vanderbilt University Medical Center, Nashville, TN 37232, Fax: (615) 343-2551, Phone: (615) 343-0665, mias.pretorius@vanderbilt.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Clinical Trial Registration Methods Study PopulationData were obtained from participants in the ongoing "The effect of atorvastatin on Acute Kidney Injury following cardiac surgery" (Statin AKI) study...
Purpose The purpose of this study was to determine the contribution of each of the ACL and medial ligament structures in resisting anteromedial rotatory instability (AMRI) loads applied in vitro. Methods Twelve knees were tested using a robotic system. It imposed loads simulating clinical laxity tests at 0° to 90° flexion: ±90 N anterior-posterior force, ±8 Nm varus-valgus moment, and ±5 Nm internal-external rotation, and the tibial displacements were measured in the intact knee. The ACL and individual medial structures-retinaculum, superficial and deep medial collateral ligament (sMCL and dMCL), and posteromedial capsule with oblique ligament (POL + PMC)-were sectioned sequentially. The tibial displacements were reapplied after each cut and the reduced loads required allowed the contribution of each structure to be calculated. Results For anterior translation, the ACL was the primary restraint, resisting 63-77% of the drawer force across 0° to 90°, the sMCL contributing 4-7%. For posterior translation, the POL + PMC contributed 10% of the restraint in extension; other structures were not significant. For valgus load, the sMCL was the primary restraint (40-54%) across 0° to 90°, the dMCL 12%, and POL + PMC 16% in extension. For external rotation, the dMCL resisted 23-13% across 0° to 90°, the sMCL 13-22%, and the ACL 6-9%. Conclusion The dMCL is the largest medial restraint to tibial external rotation in extension. Therefore, following a combined ACL + MCL injury, AMRI may persist if there is inadequate healing of both the sMCL and dMCL, and MCL deficiency increases the risk of ACL graft failure.
Purpose To define the length-change patterns of the superficial medial collateral ligament (sMCL), deep MCL (dMCL), and posterior oblique ligament (POL) across knee flexion and with applied anterior and rotational loads, and to relate these findings to their functions in knee stability and to surgical repair or reconstruction. Methods Ten cadaveric knees were mounted in a kinematics rig with loaded quadriceps, ITB, and hamstrings. Length changes of the anterior and posterior fibres of the sMCL, dMCL, and POL were recorded from 0° to 100° flexion by use of a linear displacement transducer and normalised to lengths at 0° flexion. Measurements were repeated with no external load, 90 N anterior draw force, and 5 Nm internal and 5 Nm external rotation torque applied. Results The anterior sMCL lengthened with flexion (p < 0.01) and further lengthened by external rotation (p < 0.001). The posterior sMCL slackened with flexion (p < 0.001), but was lengthened by internal rotation (p < 0.05). External rotation lengthened the anterior dMCL fibres by 10% throughout flexion (p < 0.001). sMCL release allowed the dMCL to become taut with valgus rotation (p < 0.001). The anterior and posterior POL fibres slackened with flexion (p < 0.001), but were elongated by internal rotation (p < 0.001). Conclusion The structures of the medial ligament complex react differently to knee flexion and applied loads. Structures attaching posterior to the medial epicondyle are taut in extension, whereas the anterior sMCL, attaching anterior to the epicondyle, is tensioned during flexion. The anterior dMCL is elongated by external rotation. These data offer the basis for MCL repair and reconstruction techniques regarding graft positioning and tensioning.
The present prospective study was designed to determine the prevalence of pleural effusion at approximately 28 days after cardiac surgery and their subsequent course. This consecutive case study included 389 patients; 312 had only coronary artery bypass graft surgery (CABG) surgery, 37 had both valve and CABG surgery, and 40 had only valve surgery. Chest radiographs were obtained approximately 28 days postoperatively. Patients were subsequently contacted by telephone 3, 6, and 12 months postoperatively and questioned about the presence of fluid in their chest and related symptoms. The prevalence of pleural effusions in the patients undergoing only CABG surgery (63%) or CABG surgery plus valve surgery (62%) was significantly (p = 0.05) higher than that in the patients undergoing valve surgery only (45%). The prevalence of effusions occupying more than 25% of the hemithorax was 9.7%. The primary symptom associated with these larger effusions was dyspnea. Chest pain and fever were uncommon. Over the 12-month follow-up, the effusions tended to resolve. In conclusion, the prevalence of pleural effusions occupying more than 25% of the hemithorax is approximately 10%, 28 days postoperatively. These larger pleural effusions produce dyspnea but not chest pain or fever, and most of the effusions disappear gradually over the subsequent months.
Purpose To define the bony attachments of the medial ligaments relative to anatomical and radiographic bony landmarks, providing information for medial collateral ligament (MCL) surgery. Method The femoral and tibial attachments of the superficial MCL (sMCL), deep MCL (dMCL) and posterior oblique ligament (POL), plus the medial epicondyle (ME) were defined by radiopaque staples in 22 knees. These were measured radiographically and optically; the precision was calculated and data normalised to the sizes of the condyles. Femoral locations were referenced to the ME and to Blumensaat's line and the posterior cortex. Results The femoral sMCL attachment enveloped the ME, centred 1 mm proximal to it, at 37 ± 2 mm (normalised at 53 ± 2%) posterior to the most-anterior condyle border. The femoral dMCL attachment was 6 mm (8%) distal and 5 mm (7%) posterior to the ME. The femoral POL attachment was 4 mm (5%) proximal and 11 mm (15%) posterior to the ME. The tibial sMCL attachment spread from 42 to 71 mm (81-137% of A-P plateau width) below the tibial plateau. The dMCL fanned out anterodistally to a wide tibial attachment 8 mm below the plateau and between 17 and 39 mm (33-76%) A-P. The POL attached 5 mm below the plateau, posterior to the dMCL. The 95% CI intra-observer was ± 0.6 mm, inter-observer ± 1.3 mm for digitisation. The inter-observer ICC for radiographs was 0.922. Conclusion The bone attachments of the medial knee ligaments are located in relation to knee dimensions and osseous landmarks. These data facilitate repairs and reconstructions that can restore physiological laxity and stability patterns across the arc of knee flexion.
4Purpose: The purpose of this work was to develop the rationale for adding a lateral extra-5 articular tenodesis to an ACL reconstruction in a knee with an injury that included both the 6 ACL and anterolateral structures, and to show the early clinical picture. 7Methods: The paper includes a review of recent anatomical and biomechanical studies of 8 the anterolateral aspect of the knee. It then provides a detailed description of a modified 9Lemaire tenodesis technique. A short-term clinical follow up of a case and control group was 10 performed, with two sequential groups of patients treated by isolated ACL reconstruction, and 11 by combined ACL plus lateral tenodesis. 12
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.